Yaks In China Research Articles

Genome Analysis and Safety Assessment of Achromobacter marplatensis Strain YKS2 Strain Isolated from the Rumen of Yaks in China.

Achromobacter marplatensis strain YKS2 isolated from the yak rumen has the feature of producing cellulose. This study aims to analyze the genome and safety of strain YKS2 in vivo, considering its future research and application prospects. The genome of strain YKS2 was sequenced and used for genomic in silico studies. The administration of strain YKS2 in three doses was carried out on mice for 3days of oral and 7days of clinical observation tests. The BW, FI, organ indices, gut microbiota, and histological appearances of organs and intestines, along with hematological parameters and serum biochemistry, were measured in mice. The chromosome size of strain YKS2 was 6,588,568bp, with a GC content of 65.27%. The 6058 coding sequences of strain YKS2 without plasmid were predicted and annotated and have multiple functions. The mice in all groups were alive, with good mental states and functional activities. Compared with the control group, there was no significant difference in the three dose groups on BW, FI, hematological parameters (WBC, LYM, etc.), and serum biochemistry (ALB, ALT, etc.). No abnormalities were observed in the main visceral organs, intestinal tissue, and V/C value in groups. However, the IEL number of duodenum and gut microbiota diversity (Shannon's index) in the high-dose group was significantly higher than in the control group (p < 0.05). Besides, the low dose of strain YKS2 also significantly affected the bacterial abundance of Firmicutes, Actinobacteria, and desulphurizing Bacteroidetes at the phylum level. There was no significant effect at genus levels in groups. In conclusion, the study revealedthe genome and potential functional genes of strain YKS2, which is beneficial to understanding the features of the A. marplatensis strain and proved strain YKS2 to be without acute toxicity to mice. However, a long-term feeding toxicity experiment in vivo should be performed to further ensure its potential application value strain in the animal industry.

A systematic review of economic assessments for brucellosis control interventions in livestock populations.

Brucellosis in livestock is a disease of paramount importance to animal and human health authorities due to its socio-economic and public health consequences. Benefit cost analyses can help policymakers decide whether allocation of resources is economically beneficial to cover the costs of brucellosis control interventions in populations. One broad question of interest is: what are the consequences of acting, or failing to act, on policy options of selected intervention scenarios (e.g., vaccination, test-and-slaughter, vaccination combined with test-and-slaughter, versus a status-quo scenario). The objective of the systematic review reported here was to conduct a critical appraisal of published research reports of economic assessments of brucellosis control interventions in livestock populations. The systematic review followed standard guidelines using a Population, Intervention, Comparison, Outcome, and Context framework and Preferred Reporting Items for Systematic Review and Meta-Analysis. The review targeted research reports focused on brucellosis control interventions in livestock populations at the national or regional level. Economic outcomes of interest were benefit-cost ratio (BCR), net present value, internal rate of return, or payback period. Eleven studies conducted in Brazil, China, India, Iraq, Mexico, Mongolia, Spain, Turkey, or the USA met the inclusion criteria and were included. The baseline prevalence of brucellosis in selected study populations ranged from 1.4% in cattle in Turkey to 20% in goats in Mexico. In six studies, selected intervention scenarios of vaccination alone produced BCRs that ranged from 3.2 in yaks in China or in cattle, sheep and goats in Mongolia, to 21.3 in cattle and/or buffalo in India. In three studies, interventions of test-and-slaughter produced BCRs that ranged from -1.2 in goats in Mexico to 0.6 in cattle in Spain. In four studies, vaccination in combination with test-and-slaughter produced BCRs that ranged from 0.2 in yaks in China to 3.7 in cattle and buffalo in India. In seven studies, using sensitivity analysis, different input parameters (prevalence of brucellosis, meat price, cashmere price, vaccination coverage, test-and-slaughter coverage, milk price, vaccination protection, abortion cost, abortion rate, or price of lamb) had an impact on economic outcomes. Vaccination alone was cost-effective, but test-and-slaughter was not, for brucellosis control in selected livestock populations in focus countries. Vaccination in combination with test-and-slaughter produced profitable or nonprofitable economic outcomes. While most studies reported the cost and benefits of implementing brucellosis control interventions, only one study explained socio-economic consequences of economic outcomes, when acting, or failing to act, on selected interventions in livestock populations.

Brucellosis prevalence in yaks in China in 1980–2019: A systematic review and meta-analysis

In the Qinghai-Tibet Plateau of China, the yak is an animal of particular economic interest, which provides protein and income for herders in daily life. Brucellosis is a bacterial disease that can infect humans and animals, including yaks. It can damage the yak reproductive system, causing miscarriage and orchitis. At the same time, brucellosis threatens the health of herders. We performed this meta-analysis using R software to explore the combined prevalence and risk factors of brucellosis in yak in China. Variability was assessed by the I2 statistic and Cochran Q statistic. We identified 52 publications of related research from four databases (Wanfang Data, VIP Chinese Journal Database, China National Knowledge Infrastructure, and of PubMed). The pooled prevalence of yak brucellosis was 8.39 %. Prevalence was highest in Southwestern China (11.1 %). The point estimate of brucellosis in yak from 2012 to 2016 was the highest (11.47 %). The point estimate of age ≤ 12 months (1.44 %) was lower than that of age > 12 months (15.6 %). This study shows that yak brucellosis is serious, and its incidence is higher than before 2012. We recommend carrying out large-scale yak brucellosis investigations in Western China and conducting comprehensive testing planning. The detection of brucellosis in adult animals should be strengthened to reduce the economic loss caused by brucellosis to herders and to improve public health.

Prevalence of Cryptosporidium spp. in Yaks (Bos grunniens) in China: A Systematic Review and Meta-Analysis.

Cryptosporidium spp., the causative agent of cryptosporidiosis, can infect a variety of hosts. So far, there has been limited information regarding Cryptosporidium spp. infection in yaks (Bos grunniens). Here, we performed the first systematic review and meta-analysis for Cryptosporidium spp. infection in yaks in China. To perform the meta-analysis, five databases (Chinese National Knowledge Infrastructure (CNKI), VIP Chinese journal database, WanFang Data, PubMed, and ScienceDirect) were employed to search for studies related to the prevalence of Cryptosporidium spp. in yaks in China. The total number of samples was 8,212, and the pooled Cryptosporidium spp. prevalence in yaks was estimated to be 10.52% (1192/8012). The prevalence of Cryptosporidium spp. in yaks was 13.54% (1029/5277) and 4.49% (148/2132) in northwestern and southwestern China, respectively. In the sampling year subgroups, the prevalence before 2012 (19.79%; 650/2662) was significantly higher than that after 2012 (6.07%; 437/4476). The prevalence of Cryptosporidium spp. in cold seasons (20.55%; 188/794) was higher than that in warm seasons (4.83%; 41/1228). In the age subgroup, the yaks with age < 12 months had a higher prevalence (19.47%; 231/1761) than that in yaks with age ≥12 months (16.63%; 365/2268). Among 12 Cryptosporidium spp. species/genotypes, the C. bovis had the highest prevalence. Moreover, the effects of geography (latitude, longitude, precipitation, temperature, and altitude) and climate on Cryptosporidium spp. infection in yaks were evaluated. Through analyzing the risk factors correlated with the prevalence of Cryptosporidium spp., we recommend that effective management measures should be formulated according to the differences of different geographical factors, in order to prevent cryptosporidiosis and reduce economic losses in yaks in China.

Ehrlichia chaffeensis and Four Anaplasma Species With Veterinary and Public Health Significance Identified in Tibetan Sheep (Ovis aries) and Yaks (Bos grunniens) in Qinghai, China.

Tick-borne diseases (TBDs) can cause serious economic losses and are very important to animal and public health. To date, research on TBDs has been limited in Qinghai-Tibet Plateau, China. This epidemiological investigation was conducted to evaluate the distribution and risk factors of Anaplasma spp. and Ehrlichia chaffeensis in livestock in Qinghai. A total of 566 blood samples, including 330 yaks (Bos grunniens) and 236 Tibetan sheep (Ovis aries) were screened. Results showed that A. bovis (33.3%, 110/330) and A. phagocytophilum (29.4%, 97/330) were most prevalent in yaks, followed by A. ovis (1.2%, 4/330), A. capra (0.6%, 2/330), and E. chaffeensis (0.6%, 2/330). While A. ovis (80.9%, 191/236) and A. bovis (5.1%, 12/236) infection was identified in Tibetan sheep. To our knowledge, it is the first time that A. capra and E. chaffeensis have been detected in yaks in China. Apart from that, we also found that co-infection of A. bovis and A. phagocytophilum is common in yaks (28.2%, 93/330). For triple co-infection, two yaks were infected with A. bovis, A. phagocytophilum, and A. capra, and two yaks were infected with A. bovis, A. phagocytophilum, and E. chaffeensis. Risk analysis shows that infection with A. bovis, A. phagocytophilum, and A. ovis was related to region and altitude. This study provides new data on the prevalence of Anaplasma spp. and E. chaffeensis in Qinghai, China, which may help to develop new strategies for active responding to these pathogens.

Prevalence of Bovine Tuberculosis in Yaks Between 1982 and 2020 in Mainland China: A Systematic Review and Meta-Analysis.

Bovine tuberculosis (bTB) is a major chronic bacterial disease in cattle and is the major economic and animal welfare issue in the world. Although the economic costs and public health safety risks associated with the disease are considerable, the overall epidemiology of the Chinese yak (Bos grunniens) bTB is unclear. To fully reveal the basic prevalence of yak bTB in different regions of China, we searched five databases including PubMed, Science Direct, CNKI (China National Knowledge Infrastructure), Wanfang and Chongqing VIP. Based on the incidence and prevalence of yak tuberculosis in China from 1982 to 2020, a meta-analysis of yak bTB in China was established for the first time. By formulating the search formula, 97 studies were searched in five databases. According to the established exclusion criteria and excluded comments and repeated and irrelevance research, we finally selected 19 cross-sectional studies, which showed the prevalence of bTB in Chinese yaks. Random-effect meta-regression model analysis showed that the estimated prevalence of 122,729 yaks in China was 1.0 (95% confidence interval [CI]: 0.0-1.0). The regional prevalence varies greatly, northwest China prevalence rate 0. 39% (95% CI: 0.2-0. 64) and southwest China prevalence rate 2.59% (95% CI: 1.94-3.34); in terms of province level, the prevalence was highest in Tibet 2.59% (95% CI: 1.94-3.34), followed by Xinjiang 2.36% (95% CI: 0.86-4.58), and Shanxi has the lowest 0.00% (95% CI: 0.00-0.98). This systematic review and meta-analysis identified the estimated prevalence of bTB in Chinese yaks and estimated the underlying factors associated with bTB, including geographic location, sampling year, age, and TB detection method. Provide evidence to plan corresponding disease control strategies for policymakers and to assess future economic risks accurately.

Seasonal Prevalence and Novel Multilocus Genotypes of Giardia duodenalis in Yaks (Bos grunniens) in Qinghai Province, Western China.

Background:Giardia duodenalis is an important opportunistic zoonotic intestinal protozoon, which could parasitize yaks. However, a few studies have been conducted on the seasonal infection of G. duodenalis in yaks in China.Methods:Overall, 1,027 fecal samples were collected from yaks of two age groups in seven cities of Qinghai Province, China at four seasons between May 2016 and Sep 2017. The prevalence and assemblages were analyzed by nested PCR and multilocus sequence typing (MLST).Results:The overall prevalence of G. duodenalis was 2.04% (21/1027) based on triose phosphate isomease (tpi) locus. No significant differences in prevalence of the organism in yaks were found among different sampling areas. Additionally, same result was also presented in different seasons. However, there was statistically significant difference between young yaks within 6 months (8.33%, 4/48) and adult yaks over 6 months (1.73%, 17/979). The assemblage A recognized as a zoonotic assemblage (n=3) was found in yaks (>6 months) from Xining, while assemblage E (n=18) was detected from yaks in six cities. There were 5, 2 and 3 G. duodenalis subtypes detected positive at the tpi, the β-giardin (bg), and the glutamate dehydrogenase (gdh) loci, with 2, 2 and 3 novel subtypes, respectively. Three samples were successfully sequenced at all three loci, forming 1 assemblages A multilocus genotype (MLG) and 2 assemblages E MLGs, not reported.Conclusion:This study indicated a zoonotic potential of G. duodenalis in yaks from Qinghai Province and provides basic information about the epidemiology of G. duodenalis.

High prevalence and genomic characteristics of G6P[1] Bovine Rotavirus A in yak in China.

Yak is an iconic species of the Qinghai-Tibet Plateau, which is the world's highest plateau. Here, a total of 541 yak diarrhoeic samples were collected from 69 farms in four provinces in the Qinghai-Tibet Plateau from April 2015 to June 2018, and 73.6 % of samples were detected as Bovine Rotavirus A (BRVA) positive by RT-PCR assay. Two G genotypes (G6, G10) and two P genotypes (P[1], P[11]) were determined, in which G6P[1] BRVA was the predominant strain. Moreover, VP7 and VP4 of these G6P[1] strains showed unique amino acid mutations, such that they clustered into an independent branch in the phylogenetic tree. A strain of BRVA designated as RVA/Yak-tc/CHN/QH-1/2015/G6P[1] was isolated successfully using MA104 cells, and the virus titre was determined as 105.84 TCID50 ml-1. The genome of strain QH-1 had a G6-P[1]-I2-R2-C2-M2-A3-N3-T6-E2-H3 genotype constellation. QH-1 was identified as a reassortment strain of BRVA, human RVA and ovine RVA based on the nucleotide identity and phylogenetic tree of 11 gene segments, indicating its public health significance. To the best of our knowledge, this is the first report on the molecular prevalence and genome characteristics of BRVA in yak, contributing to further understanding of the epidemic and genetic evolution of BRVA.

Sarcosporidiosis: An Emerging Disease in Yaks (Bos grunniens) on the Qinghai Tibetan Plateau (QTP), China

Sarcocystosis is a worldwide distributed parasitic zoonosis. However, scarce knowledge is available about the infection of sarcocystosis in yaks. Herein, we conducted this study to survey the seroprevalence of sarcocystosis in yaks on the Qinghai Tibetan plateau. A total of 2549 serum samples were obtained during 2011-2017, which were assayed using commercial ELISA kits. The results revealed that the overall seroprevalence of sarcosporidiosis in QTP yaks was 0.90% (95 CI 0.6-1.4). The seroprevalence ranged from 0.20% (95 CI 0-1.1) to 1.67% (95 CI 0.8-3.0) in yaks in different areas. The seroprevalence was 0.73% (95 CI 0.3-1.4) in male yaks and 0.06% (95 CI 0.6-1.8) in female yaks. In different ages, the seroprevalence ranged from 0 (95 CI 0-1.4) to 1.47% (95 CI 0.6-3.0). In different years, the seroprevalence ranged from 0 (95 CI 0-1.4) to 1.86% (95 CI 0.7-4.0). In the current study herein, region and age were revealed to be the obvious influencing risk factors by conditional stepwise logistic regression. The current study herein first found the emerging infection of sarcosporidiosis in yaks from high plateaus, which contributes to outline the epidemiological scenario of sarcosporidiosis in yaks in China. Moreover, our findings highlight the urgent need of studies in yaks on the QTP at further and more comprehensive level.

Mitochondrial genome data confirm that yaks can serve as the intermediate host of Echinococcus canadensis (G10) on the Tibetan Plateau

BackgroundCervids used to be considered the only animal intermediate hosts of the G10 genotype of Echinococcus canadensis. Yaks are often herded in the Qinghai-Tibet Plateau, China, where echinococcosis remains prevalent. However, no E. canadensis G10 cases have been recorded in yaks until now. The aim of our study was to identify causative agents of echinococcosis in yaks in this region.MethodsTotal genomic DNA was extracted from the germinal layer of one hydatid using a Blood and Tissue Kit. Full-length mitochondrial (mt) cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes were amplified by PCR. All purified PCR products were directly sequenced in both directions. Then seven pairs of overlap primers were designed to amplify the entire mt genome sequence of a suspected E. canadensis G10 isolate. Phylogenetic analyses were performed based on concatenated nucleotides from the 12 protein-coding genes of mt genomes of Echinococcus species in a Bayesian framework using MrBayes v3.1 and implementing the GTR + I + G model.ResultsHydatids were found in yaks (n = 129) when organs were inspected at the slaughterhouse in Maqu county, Gannan Tibetan Autonomous Prefecture, Gansu Province, China in October 2016. Of these, 33 (25.6%) harbored up to a dozen hydatid cysts. One cyst from each yak was characterized by sequencing its mitochondrial (mt) cox1 and nad1 genes. On the basis of these sequence data, 32 cysts were identified as Echinococcus granulosus (sensu stricto) (G1-G3) and the remaining one was identified as the G10 genotype of E. canadensis. Its mt genome was then fully sequenced and compared with that of the G10 genotype in GenBank (AB745463). Phylogenetic analysis using complete mt genomes confirmed the Chinese cyst as belonging to the G10 genotype.ConclusionsTo our knowledge, this is the first report globally of E. canadensis (G10) from yaks in China, which suggests that the G10 genotype has a wider geographical distribution and broader host range than previously believed. This genotype has therefore potential risks to human health and animal husbandry.

Seroprevalence and Risk Factors of Bluetongue Virus Infection in Tibetan Sheep and Yaks in Tibetan Plateau, China.

Bluetongue (BT), caused by bluetongue virus (BTV), is an arthropod-borne viral disease in ruminants. However, information about BTV infection in yaks in China is limited. Moreover, no such data concerning BTV in Tibetan sheep is available. Therefore, 3771 serum samples were collected from 2187 Tibetan sheep and 1584 yaks between April 2013 and March 2014 from Tibetan Plateau, western China, and tested for BTV antibodies using a commercially available ELISA kit. The overall seroprevalence of BTV was 17.34% (654/3771), with 20.3% (443/2187) in Tibetan sheep and 13.3% (211/1584) in yaks. In the Tibetan sheep group, the seroprevalence of BTV in Luqu, Maqu, Tianzhu, and Nyingchi Prefecture was 20.3%, 20.8%, 20.5%, and 19.1%, respectively. The seroprevalence of BTV in different season groups varied from 16.5% to 23.4%. In the yak group, BTV seroprevalence was 12.6%, 15.5%, and 11.0% in Tianzhu, Maqu, and Luqu counties, respectively. The seroprevalence in different seasons was 12.6%, 15.5%, 15.4%, and 9.0% in spring, summer, autumn, and winter, respectively. The season was the major risk factor concerning BTV infection in yaks (P < 0.05). The date of the BTV seroprevalence in Tibetan sheep and yaks provides baseline information for controlling BT in ruminants in western China.

Seroprevalence and risk factors of bovine viral diarrhoea virus (BVDV) infection in yaks (Bos grunniens) in northwest China.

Bovine viral diarrhoea virus (BVDV), a member of the Pestivirus genus, is an important pathogen of cattle worldwide, causing reproductive disorders in adult cattle and mucosal disease in calves. However, limited information about BVDV infection in yaks (Bos grunniens) in China is available, especially in white yaks which is a unique yak breed that only lives in Tianzhu Tibetan Autonomous County (TTAC), Gansu Province, northwest China. Therefore, we conducted a cross-sectional study to estimate the seroprevalence and risk factors associated with BVDV infection in 1584 yaks in Gansu province, northwest China, between April 2013 and March 2014 using an indirect ELISA test. The overall seroprevalence of BVDV in yaks was 37.56% (595/1584), with 45.08% (275/610) in black yaks and 32.85% (320/974) in white yaks. Moreover, positive yaks were found in all four regions, varied from 33.22 to 40.31%. Male yaks had a similar seroprevalence (37.84%) with that of the female yaks (37.11%). Season, species and geographical origins of yaks were considered as risk factors analyzed by logistic regression model. To our knowledge, this is the first report of seroprevalence and risk factors associated with BVDV infection in white yaks in China.

First Report of Bovine Leukemia Virus Infection in Yaks (Bos mutus) in China.

Enzootic bovine leukosis (EBL) is a chronic lymphosarcoma disease of cattle caused by bovine leukemia virus (BLV). No information is available concerning the epidemiology of BLV infection in yaks (Bos mutus). One thousand five hundred and eighty-four serum samples from 610 black yaks and 974 white yaks from Gansu province, northwest China, were collected between April 2013 and March 2014 and tested for BLV antibodies using a commercially available ELISA kit. The overall BLV seroprevalence in yaks was 21.09% (334/1584), with 24.26% (148/610) black yaks and 19.10% (186/974) white yaks yielding positive results. Risk factor analysis indicated that with the exception of breed (OR = 1.36, 95% CI = 1.06–1.73, P < 0.05), the age, region, gender, farm, and the numbers of pregnancies were not considered as risk factors for the presence of BLV in yaks included in this study. This is the first report of BLV infection in yaks in China, which provides information for controlling BLV infection in yaks.

Molecular characterization of Giardia duodenalis from white yaks in China.

Giardia duodenalis is one of the most common enteric parasites of humans and animals, including companion animals, livestock and wildlife. To date, the information about the prevalence and molecular characterization of G. duodenalis infection in white yaks was limited. In the present study, a total of 208 white yak fecal samples were collected from Tianzhu Tibetan Autonomous County (TTAC) between September 2013 and March 2014. Of the 208 white yak fecal samples, four samples (1.92%, all collected in March 2014) tested G. duodenalis-positive by PCR amplification of triosephosphate isomerase (tpi) gene. Sequence analysis confirmed the presence of G. duodenalis assemblage E. The present study revealed the presence and genotype of G. duodenalis in white yaks for the first time, and extended the host range of G. duodenalis. These results provided useful information for further genotyping or subtyping studies of G. duodenalis in white yaks.

Genetic characterization and molecular survey of Babesia bovis, Babesia bigemina and Babesia ovata in cattle, dairy cattle and yaks in China.

BackgroundBabesiosis is an important haemoparasitic disease, caused by the infection and subsequent intra-erythrocytic multiplication of protozoa of the genus Babesia that impacts the livestock industry and animal health. The distribution, epidemiology and genetic characterization of B. bigemina, B. bovis, and B. ovata in cattle in China as well as the prevalence of these protozoan agents were assessed.MethodsA total of 646 blood specimens from cattle, dairy cattle and yaks from 14 provinces were collected and tested for the presence of the three Babesia species via a specific nested PCR assay based on the rap-1 and ama-1 genes. The PCR results were confirmed by DNA sequencing. Gene sequences and the genetic characterization were determined for selected positive samples from each sampling area.ResultsOf a total of 646 samples, 134 (20.7 %), 60 (9.3 %) and 10 (1.5 %) were positive for B. bovis, B. bigemina and B. ovata infections, respectively. Mixed infections were found in 7 of 14 provinces; 43 (6.7 %) samples were infected with B. bovis and B. bigemina. Three samples (0.5 %) exhibited a co-infection with B. bovis and B. ovata, and 6 (0.9 %) were infected with all three parasites. The rap-1a gene of B. bovis indicated a high degree of sequence heterogeneity compared with other published rap-1a sequences worldwide and was 85–100 % identical to B. bovis rap-1a sequences in Chinese isolates. B. bigemina rap-1c and B. ovata ama-1 genes were nearly identical, with 97.8–99.3 % and 97.8–99.6 % sequence identity, respectively, in GenBank.ConclusionsPositive rates of B. bovis and B. bigemina infection are somewhat high in China. The B. bovis infection in yaks was first reported. The significant sequence heterogeneity in different variants of the rap-1a gene from Chinese B. bovis isolates might be a great threat to the cattle industry if RAP-1a protein is used as immunological antigen against Babesia infections in China. The data obtained in this study can be used to plan effective control strategies against babesiosis in China.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1110-0) contains supplementary material, which is available to authorized users.

First serologic survey of Q fever in free-range yaks in China.

The objective of the present investigation was to determine the seroprevalence of Coxiella burnetii infection in free-range yaks in China. A total of 552 serum samples were collected from yaks in Gansu province, northwest China between April 2013 and January 2014, and antibodies against C. burnetii were evaluated using enzyme-linked immunosorbent assay (ELISA). Overall, 13.59% (75/552, 95% CI: 10.73-16.45) of the examined animals were positive for C. burnetii antibodies. There was no significant difference in C. burnetii seroprevalence between female yaks (13.78%, 95% CI: 10.36-17.19) and male yaks (13.13%, 95% CI: 7.89-18.36) (P>0.05). Coxiella burnetii seroprevalence in yaks in different age groups ranged from 10.88% to 15.26%, but the difference was not statistically significant (P>0.05). Coxiella burnetii seroprevalence in yaks sampled in different seasons ranged from 12.06% (autumn) to 18.33% (summer), but the difference was not statistically significant (P>0.05). This is the first report of C. burnetii seroprevalence in free-range yaks in China, indicating the need for measures to be taken to control C. burnetii infection in free-range yaks in China.

First report of Babesia bigemina infection in white yaks in China

White yaks, a unique yak breed and the pearl of the plateau, only live in Tianzhu Tibetan Autonomous County (TTAC), Gansu Province, northwest China, contributing significantly to local economy. However, there was no information on the prevalence of Babesia bigemina in white yaks. In this study, a total of 974 serum samples collected from white yaks in TTAC were examined for specific antibodies against B. bigemina using a commercially available ELISA kit. The overall seroprevalence of B. bigemina in white yaks was 17.76% (173/974). A multivariate logistic regression analysis was performed to determine the risk factors associated with B. bigemina seroprevalence, and the results indicated that age, gender and the numbers of pregnancies of white yaks were not the significant risk factors. However, the white yaks in spring (OR=3.523, 95% CI=1.899–6.538, P<0.001) and summer (OR=3.439, 95% CI=1.909–6.193, P<0.001) encountered higher risk of being exposed to B. bigemina than that in winter. Thus, season was considered as a risk factor associated with B. bigemina infection. This is the first survey of B. bigemina seroprevalence in white yaks in China, which extends the host range for B. bigemina and provides useful information for controlling B. bigemina infection in white yaks.

Seroprevalence and risk factors of Chlamydia abortus infection in free-ranging white yaks in China

BackgroundChlamydia is gram-negative obligate bacteria which causes a wide variety of diseases in humans and animals. To date, there are a few reports about the seroprevalence of Chlamydia and the risk factors associated with Chlamydia infection in yaks in the world. In this study, 974 blood samples were collected from white yaks (Bos grunniens) in Tianzhu Tibetan Autonomous County, Gansu province, northwest China from June 2013 to April 2014.ResultsAntibodies against Chlamydia abortus were examined by the indirect hemagglutination (IHA) test, and 158 of 974 (16.22%) white yaks were seropositive for C. abortus antibodies at the cut-off of 1:16. The risk factors associated with seroprevalence were evaluated by a multivariate logistic regression analysis. Region, gender and age of white yak were left out of the final model, due to its insignificance in the logistic regression analysis (P > 0.05). However, season was considered as a major risk factor associated with C. abortus infection in white yaks.ConclusionsTo our knowledge, this is the first survey of C. abortus seroprevalence in white yaks in China, which extends the host range for C. abortus and has important implications for public health and the local Tibetan economy.

Methane emission inventories for enteric fermentation and manure management of yak, buffalo and dairy and beef cattle in China from 1988 to 2009

Large ruminant production systems (dairy, beef, buffaloes and yaks) in China have experienced significant changes during the last 30 years driven by increased demand for milk and meat consumption and discontinued use of beef cattle and buffaloes as draft animals. The present study aimed to evaluate the effects of these changes on methane (CH4) emissions from enteric fermentation and manure management in large ruminants in China. The emissions were developed using Tier 1 and 2 methodologies of the International Panel on Climate Change. The Tier 2CH4 emission for each species was a sum of emissions calculated from several groups based on their physiological states, e.g. milking cows, dry cows, sires and steers/heifers at various ages. Total CH4 emission inventory for dairy cattle, beef cattle, buffaloes and yaks in China increased gradually from 5530 to 6761Gg/year or 4514 to 5777Gg/year calculated using the Tier 1 or 2 method during the period of 1988–2009. This increase was driven by increased population and production of dairy and beef cattle (e.g. Tier 2CH4 emissions increased respectively from 125 to 1028Gg/year and from 2915 to 3689Gg/year). However, during the same period Tier 2CH4 emissions from buffaloes and yaks reduced from 860 to 593Gg/year and 614 to 467Gg/year, respectively. Beef cattle were main emitters which produced 63.8% of total emissions in 2009, followed by dairy cattle (17.8%), buffaloes (10.3%) and yaks (8.1%). There was a large difference in provincial contributions. In 2007, the 3 highest emission provinces (Sichuan, Tibet and Henan) each contributed 8.5–10.5% to national emissions, and the lowest 3 accounted for only 0.1–0.2% (Beijing, Zhejiang and Shanghai). The uncertainties associated with these inventories were discussed. These results provide benchmark information for Chinese authorities to develop appropriate policies and mitigation strategies to reduce carbon footprint in the large ruminant production sector in China.

Phylogeny of Theileria buffeli genotypes identified in the South African buffalo (Syncerus caffer) population

Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and buffalo in various parts of the world. In a previous study, we identified T. buffeli in blood samples originating from the African buffalo (Syncerus caffer) in the Hluhluwe–iMfolozi Game Park (HIP) and the Addo Elephant Game Park (AEGP) in South Africa. The aim of this study was to characterise the 18S rRNA gene and complete internal transcribed spacer (ITS1-5.8S-ITS2) region of T. buffeli samples, and to establish the phylogenetic position of this species based on these loci. The 18S rRNA gene and the complete ITS region were amplified from DNA extracted from blood samples originating from buffalo in HIP and AEGP. The PCR products were cloned and the resulting recombinants sequenced. We identified novel T. buffeli-like 18S rRNA and ITS genotypes from buffalo in the AEGP, and novel Theileria sinensis-like 18S rRNA genotypes from buffalo in the HIP. Phylogenetic analyses indicated that the T. buffeli-like sequences were similar to T. buffeli sequences from cattle and buffalo in China and India, and the T. sinensis-like sequences were similar to T. sinensis 18S rRNA sequences of cattle and yak in China. There was extensive sequence variation between the novel T. buffeli genotypes of the African buffalo and previously described T. buffeli and T. sinensis genotypes. The presence of organisms with T. buffeli-like and T. sinensis-like genotypes in the African buffalo could be of significant importance, particularly to the cattle industry in South Africa as these animals might act as sources of infections to naïve cattle. This is the first report on the characterisation of the full-length 18S rRNA gene and ITS region of T. buffeli and T. sinensis genotypes in South Africa. Our study provides invaluable information towards the classification of this complex group of benign and mildly pathogenic species.